5 replies to this topic

[dhns]

Dear all,

I have one doubt along with me, regarding one shell and Tube Heat Exchanger
Pressure data !

In one of my Past designed Shell and Tube Heat Exchanger data sheet
I saw the Tube side design pressure is less than the shell side operating Pressure,
It is Possible ,Let me kindly explain anybody.,
the Process Fluids are
Tubeside :sea water
Shell side: Crude stream(oil+water+gas)


Regards,
Dhns.

[gvdlans]

It is possible provided that the tube side is sufficiently protected against tube leakage, tube rupture. Protection can be with Pressure Safety Valve(s), Rupture Disk(s) or by ensuring that there is always an open path to the sea water outlet. You may also have to consider dynamic effects in case of tube rupture, see API Std 521, section on Heat Transfer Equipment Failure.

[fallah]

It is possible provided that the tube side is sufficiently protected against tube leakage, tube rupture. Protection can be with Pressure Safety Valve(s), Rupture Disk(s) or by ensuring that there is always an open path to the sea water outlet. You may also have to consider dynamic effects in case of tube rupture, see AP Std 521, section on Heat Transfer Equipment Failure.

There is no need to PSV on tube side if tube side design pressure would be equal or more than 2/3 of shell side design pressure.

[gvdlans]

There is no need to PSV on tube side if tube side design pressure would be equal or more than 2/3 of shell side design pressure.

This "2/3 rule" is outdated, see previous discussions on this forum, as well as the latest edition of API Std 521. Pressure relief for tube rupture is not required if the requirements of API Std 521 section 5.19.2 are met.

[fallah]

This "2/3 rule" is outdated, see previous discussions on this forum, as well as the latest edition of API Std 521. Pressure relief for tube rupture is not required if the requirements of API Std 521 section 5.19.2 are met.

You are right.

2/3 rule was used as per API 521 Ver. 1997 because hydrotest pressure for equipment was considered as 1.5*design pressure.

Now as per API 521 Ver. 2007,because of equipment hydrotest is performed based on 1.3*design pressure,10/13 rule is used.

Thus,low pressure side of heat exchanger shall not be subjected to pressure more than relevant corrected hydrotest pressure or in other word, design pressure of low pressure side shall be 10/13 that of high pressure side ,as minimum.

I just wanted to refer to above important point in my previous post, generally,because had been ignored in your first post.

[gvdlans]

Fallah,

This has been discussed in detail before (incl by yourself). 2/3 rule has not been replaced by a 10/13 rule. See a.o. the thread below http://www.cheresour...hl=tube rupture